Maybe it's moving on... maybe he's grieving and doesn't want people (you) on his media to see his progress. How long has it been? Who initiated the break up? Guys still go through a process of "mourning" but it can be faster depending on who hurt who.

8 months is definitely enough time to be over you :/Why did you even have to tell his gf about his sex life? Were you just trying to meddle?By sex addiction do you mean he's a nymphomaniac... or just really likes sex?